XS::APItest: test newSVpvf with blank format string

Author: mauke

MANIFEST

@@ -5156,6 +5156,7 @@ ext/XS-APItest/t/my_strtod.t			XS::APItest: test my_strtod
 ext/XS-APItest/t/newAV.t			XS::APItest: test newAV* functions
 ext/XS-APItest/t/newCONSTSUB.t			XS::APItest: test newCONSTSUB(_flags)
 ext/XS-APItest/t/newDEFSVOP.t			XS::APItest: test newDEFSVOP
+ext/XS-APItest/t/newSVpvf.t			XS::APItest: test newSVpvf
 ext/XS-APItest/t/Null.pm			Helper for ./blockhooks.t
 ext/XS-APItest/t/op.t				XS::APItest: tests for OP related APIs
 ext/XS-APItest/t/op_contextualize.t		test op_contextualize() API

ext/XS-APItest/APItest.pm

@@ -4,7 +4,7 @@ use strict;
 use warnings;
 use Carp;
 
-our $VERSION = '1.42';
+our $VERSION = '1.43';
 
 require XSLoader;
 

ext/XS-APItest/APItest.xs

@@ -5032,6 +5032,15 @@ sv_regex_global_pos_set(SV *sv, STRLEN pos, U32 flags = 0)
 void
 sv_regex_global_pos_clear(SV *sv)
 
+SV *
+newSVpvf_blank()
+    CODE:
+        GCC_DIAG_IGNORE_STMT(-Wformat-zero-length);
+        RETVAL = newSVpvf("");
+        GCC_DIAG_RESTORE_STMT;
+    OUTPUT:
+        RETVAL
+
 MODULE = XS::APItest PACKAGE = XS::APItest::AUTOLOADtest
 
 int

ext/XS-APItest/t/newSVpvf.t

@@ -0,0 +1,12 @@
+#!perl
+use strict;
+use warnings;
+
+use Test::More;
+
+use XS::APItest qw(newSVpvf_blank);
+
+# gh #23393 - empty format string crashes newSVpvf
+is newSVpvf_blank, "", 'newSVpvf("") returns "" without crashing';
+
+done_testing;